Take-All disease is a serious problem in the production of cereals, particularly wheat and barley. It is caused by the soil-borne fungus Gaeumannomyces graminis (Gg). The fungus infects the roots of the plant, and grows throughout the root tissue, causing a black rot. The growth of the fungus in the roots and lower stem prevents the plant from obtaining sufficient water and/or nutrients from the soil, and is manifested as poor plant vigor and, in severe instances of disease, by the formation of "whiteheads," which are barren or contain few, shriveled grains. Yield losses result. Gaeumannomyces species also infect other cereal crops, for example, rice and oats; and turf.
Currently the primary means of avoiding crop loss due to infestation of the soil by Gg has been to rotate the crop grown to one which is resistant to Gg. However, in areas where the primary crops are cereals, rotation is not a desirable practice, and an effective control agent is greatly desired.
It is an object of this invention to provide compounds that provide superior and unexpected control of the growth of Gg in the soil so as to reduce crop loss. It is a further object of this invention to provide an effective method for superior and unexpected control of Take-all disease in plants. It is still a further object of this invention to provide fungicidal compositions that may be used for superior and unexpected control of Take-all disease.
The international patent application PCT/US92/08633 discloses a broad scope of compounds effective against Take-all disease. The present invention are selected compounds having superior and unexpected effectiveness against the present disease.
References related to the processes of the present invention are Synth. Commun., 14, 621 (1984) and Synthesis 303, (April, 1978).
Gajda, T. and Zwierzak, A. in "Phase-Transfer-Catalysed N-Alkylation of Carboxamides and Sulfonamides" published in Synthesis, pp.1005-7, December 1981 and Abiko, A. et al. in "KMnO.sub.4 Revisited: Oxidation of Aldehydes to Carboxylic Acids in the tert-Butyl Alcohol--Aqueous NaH.sub.2 PO.sub.4 System" published in Tetrahedron Letters, Vol.27, No. 38, pp. 4637-4540, 1986 are additional references related to the processes of the present invention. Additionally, related abstracts include Derwent Abstract Nos., 87-203436/29, 89-013361/02, 90-213193/28, 91-061915/09, 93-062565/08 and 93-096743/12.